Recently, Asato et al. [16] and Fraga et al. [17] analyzed the phylogeny of genus Leishmania using the sequences obtained from the cyt b and the hsp70
regions and demonstrated the improvement of Leishmania classification from the traditional method proposed by Lainson and Shaw [30]. Their studies showed that these genes contained sufficient information for distinguishing species/subspecies and also human/nonhuman Leishmania. The high GS-1101 datasheet congruency between the cyt b and the hsp70 trees corresponding to the current classification were, thus, logically acceptable as the precise relationship of genus Leishmania. Employing the L. siamensis taxa into these trees provided more knowledge of this species in relation to other previously identified Leishmania species. Previous
studies showed the early divergence of L. enrietti from other Leishmania groups, closely related to genus Endotrypanum, LY333531 ic50 suggesting that this species may not belong to genus Leishmania [16]. In this study, grouping between both lineages of L. siamensis and RXDX-101 cost L. enrietti rearranged the phylogenetic position of L. enrietti compared with a previous tree shown by Asato et al. [16]. The close relationship between lineage TR (previously described as Trang strain) and L. enrietti was supported by our previous work using concatenated sequences of three Leishmania protein-coding genes to construct the tree [8]. As shown in this study, L. enrietti and L. siamensis formed Farnesyltransferase independent sister clades and shared the same branch of the members classified as Euleishmania, leaving the group of Paraleishmania completely separated. This finding distinctly indicated that they might be part of an unclassified subgenus of Leishmania. Unfortunately,
the hsp70 sequences of L. enrietti and other species belonging to Paraleishmania were not available in the GenBank, and the alternative notion of this idea could not be obtained by the hsp70 tree in this study. However, the phylogenetic position of L. siamensis was in good agreement between the hsp70 and the cyt b trees in that these species were members of neither L. (Leishmania) nor L. (Viannia) and they should be regarded as an unclassified subgenus. Since the identification of L. siamensis from a Thai VL case has been described using the comparison of mini-exon and ITS1 sequences in 2008 [7], more cases presumably caused by the same Leishmania species were reported on other continents. In 2009, autochthonous cutaneous leishmaniasis (CL) was reported in horses and a cow in Switzerland and Germany, followed by an additional case in a mare from the USA in 2012 [31–33]. These cases showed high ITS1 similarity compared with those previous reports of L. siamensis. To elucidate the relationship among the Leishmania detected from these cases and L. siamensis, these sequences were phylogenetically analyzed. The phylogenetic tree of ITS1 region, again, separated the L. siamensis lineage TR from lineage PG.